Honing tool



April 30, 1968 P. FITZPATRICK HON IN G TOOL 4 Sheets-Sheet 1 Filed Sept. 20, 1965 INVENTOR WA 04 F/I'ZPAT/F/C/f ATTORNEYS April 30, 1968 P. FlTZPATRlCK 3,380,197

HONING TOOL Filed Sept. 20, 1965 4 Sheets-Sheet 2 1.90 lac 23o 234 INVENTOR.

P14 F/TZPfiT/Q/CK 244 ATTORNEVS April 30, 1968 P. FITZPATRICK HONING TOOL 4 Sheets-Sheet (5 Filed Sept. 20, 1965 FIG. 3

FIG. 4

INVENTOR. 1 404 F/TZP/QT/P/CK 6M af g Z ATTORNEYS April 30, 1968 P. FITZPATRICK 3,380,197

HONING TOOL Filed Sept. 20, 1965 4 Sheets-Sheet 4 INVENTOR. A4 04 -F/7'ZPA rem- A 7' TORNEYS United States Patent 3,380,197 HONING TOOL Paul Fitzpatrick, Bloomfield Hills, Micln, assignor to Micromatic Hone Corporation Filed Sept. 20, 1965, Ser. No. 488,337 4 Claims. (Cl. 51-34) ABSTRACT OF THE DESCLOSURE A brake drum honing tool having means to provide for eccentric adjustment of the honing tool by lateral movement, which includes a bronze ring having radially extending recesses spaced at 90 degrees with respect to each other and pin means to allow movement of said honing tool body with respect to the drive shaft assembly. To 10- cate and retain the honing tool onto a workpiece, a locator arbor is mounted to the arbor holder and adapted to lock on or hold the workpiece in a stationary position as the shiftable abrasive members of the honing tool reciprocate and rotate irregardless of eccentricity or misalignment.

This invention relates to an improved honing tool, and in particular a honing tool for honing the inner wall of a circular workpiece.

An object of the invention is to provide for honing or lapping the inner wall of a brake drum or other cylindrical body having a closure or other obstacle at one of its ends, or within its bore, which interferes with the movement of the tool entirely through the workpiece.

Another object of this invention is to provide a honing tool capable of rotary movement and for axial movement for translation of the tool throughout the length of the area to be honed on a workpiece.

Another object of this invention is to provide for a lateral shift of the abrasive body portion of the honing tool in order to compensate for eccentric stone wear.

Another object of this invention is to provide a honing device for effecting successive honing operations which is adapted for compensating adjustment automatically to maintain constant honing pressures on the surface honed.

Another object of this invention is to provide an improved method and apparatus capable of establishing a high degree of honing geometry on the finished faces of a workpiece.

Another object of this invention is to provide a honing tool of the type movable into and out of a work engaging position as a unit.

Another object of this invention is to provide a honing tool of the type adapted to be reciprocated during the honing operation.

Another object of this invention is to provide for automatically gaging abrasive stone wear.

Another object of this invention is to provide for a constant controlled force on the abrasive stones to maintain constant honing pressures.

To the accomplishment of the foregoing, and subordinate objects presently appearing, a preferred embodiment of my invention is illustrated in the accompanying drawings, set forth in detail in the succeeding description, and defined in the claims appended hereto.

In the drawings:

FIG. 1 is a perspective view of a honing machine embodying the principles of the present invention;

FIG. 2 is an enlarged cross-sectional view of the honing tool assembly;

FIG. 3 is a sectional view of the structure of FIG. 2 taken along the line 3-3 thereof;

FIG. 4 is a sectional view of the structure of FIG. 2 taken along the line 44 thereof;

FIG. 5 is a schematic diagram of the circuit;

333,197 Patented Apr. 30, 1968 FIG. 6 is a perspective view of the floating ring; and FIG. 7 is a perspective view of the feed piston.

The present invention deals with a method and apparatus adapted to finish the inner walls of brake drums to a high degree of accuracy. The invention includes an improved honing tool of simple but sturdy construction adapted to finish the surfaces with a highly accurate surface finish, finish pattern and dimension control. A frame is provided which rigidly supports the workpiece. The honing tool assembly is adapted to move into and out of a work engaging position as a unit. Thus by rotating the honing tool assembly and simultaneously reciprocating the honing tool assembly the inner wall of the brake drum will be accurately finished.

Referring now more specifically to the drawings, FIG. 1 illustrates a honing machine which is seen to include a base 10 to which an upright frame 12 is suitably affixed. A fixture frame 14 is suitably supported upon the base 10 and is adapted to support and position a workpiece during the finishing operation. In the illustrated embodiment, a workpiece consisting of a conventional automotive brake drum 16 is supported on suitable fixtures 18.

A hydraulic cylinder 20 is suitably fixed to the frame 12 and has disposed therein a quill 22 for vertical movement relative thereto. A suitable source of hydraulic fluid is adapted to be supplied to the cylinder in the usual manner by a means (not shown) to cause vertical reciprocation of the piston. A lower spindle bearing 24 is connected integral with the lower end of piston 22 and is adapted to reciprocate vertically with piston 22.

Disposed within the cylinder and extending therethrough is a spindle shaft 26 which is adapted to be rotated through a conventional belt and pulley means 28 by a motor (not shown). On the lower extremity of the spindle shaft 26 an adapter flange 30 is connected thereto for the purpose of connecting the honing tool assembly thereto by any suitable means.

A control panel 32 comprising switches and signals is mounted upon the machine frame 10.

The honing tool assembly 40, best shown in FIG. 2, comprises a drive shaft assembly 42, a body assembly and a body flange assembly 165. The drive shaft assembly comprises an adapter flange 44 adapted to be connected to the adapter flange 30 by any conventional means. The adapter flange 44 is formed integrally with a tubular shaft 46 which at its lower end is further integrally connected to a bell-shaped adapter 48.

The drive shaft assembly is connected to the body assembly 50 by means of any suitable means, such as a socket head cap screw 52, which is threadedly secured to the body housing 54. The body housing 54 has an upper annular portion 56 and a side portion 58. The surface 60 at the upper annular portion 56 abuts the surface 62 and an inner radial surface 64 of body housing 54 abuts the outer radial surface 66 of adapter 48.

Within the drive shaft 42 is a tubular body portion 70 with the smaller diametrical tubular portion 72 extending within the driveshaft assembly 42. The tubular body portion is closed at its top end portion 74. Within the smaller diametrical tubular portion 72 a piston 76 is adapted for vertical reciprocating movement. The piston 76 is provided with an O-ring 78 to sealingly engage the inner Wall of the tubular portion 72. A push rod or shaft 80 extends centrally through the piston 76 and held in secure relationship by means of a rod end 82 held by a socket held cap screw 84. Thus, the piston 76 is held in secure relationship by the push rod 80 by means of rod end 82 and a shoulder abutment 86 On the push rod 80. The piston is adapted to travel in its uppermost direction until the rod end 82 contacts the closed top end portion 74 and in its lowermost travel direction the piston will extend as far as the seal bushing 88. The seal bushing is provided with conventional O-ring 89 to sealingly-engage'the inner walls of the tubular portion 72, and O-ring 90 to sealingly engage the push rod or shaft 80. A snap ring 92 holds the seal bushing 88 in secure relationship and helps to limit the extent of the piston 76 in its travel.

The push rod 80 is connected to the expander 94 by means of a reduced shoulder portion 95 held by a split ring retainer 96 which is then secured to the expander 94 by means of socket head cap screws 98. Thus it is apparent that movement of piston 76 will cause movement of the expander 94 for the purpose to be hereinafter disclosed.

In the upper tubular portion 72 of the body 70 and extending diametrically through the closed top end portion 74 is a bore 100. Another bore 102 extends transversely to and connects with the bore and extends parallel to the axis of the honing tool shaft. A plug 104 seals the port after drilling operations have been completed. A rod 106 is provided with an O-ring 108 to sealingly engage the inner wall of the bore 102 for the purpose to be hereinafter disclosed. At the terminal portion of the bore 100 a conventional fitting 110 is threadedly connected with a pneumatic coupling 112 attached thereto. A line 113 connected to the coupling 112 is connected to a single fluid circuit for controlling stone wear, see FIG. 5. In this arrangement, a filter 114 is connected in a supply line 115 which is joined by a line 116 to a pressure regulating device 118 of conventional form. Air under regulated pressure is conducted through a control valve 120 wherein the rate of flow is controlled by a needle 122. The air flowing from the valve 120 is directed by a conduit 124 to a pressure diaphragm 126. The conduit 113 communicating with conduit 124 is connected to the honing tool by means of coupling 112. A conduit 133 may also be connected to the conduit 124 and to a gauge 134 to provide visual indication of the pressure in the circuit.

The diaphragm 126 is connected to a rod 136. The rod 136 includes a conducting bar 138 for the purpose of bridging contacts 140. Before the operation, when the air is freely flowing through bore 102 and outlet port 144, the needle 122 is carefully adjusted to permit the pressure diaphragm 126 to retract the bar 138 and bridge the contacts 140. When restriction is provided to the flow of air, as by means of rod 106 sliding in bore 102 thereby preventing ar from escaping through outlet port 144, the back pressure in the conduits 113 and 124 causes the pressure diaphragm 126 to move the conducting bar 138 outwardly. This will occur when the abrasive stones are not sufliciently worn as to require replacement. As the abrasive stones begin to wear, the rod 106 having one end bearing against the expander 94 is adapted to slide down the bore 102. When the other end of the rod 106 reaches the outlet port 144, the air will escape through outlet port 144 and the back pressure in the conduit 113 will reduce causing the pressure diaphragm 126 to drop the conducting bar 138 to bridge the contacts 140 and indicate that the abrasive stones are worn and replacement is necessary. The honing operation may be discontinued by the circuit completed by the bridging of the contacts 140 in the following manner.

The completion of the circuit through the contacts 140 energizes a relay 142 which opens the normally closed contacts 143 thereby deenergizing the motor relay M. Die-energizing the motor relay M discontinues the operation of the motor until the operator replaces the worn abrasive stones. The completion of the circuit through the contacts 140 energizes relay 128 which closes contact 129 to energize light R which is adapted. to provide a visual indication that the abrasive stones are worn and need replacing. Upon insertion of the new abrasive stones, the rod 106 will be moved so as to cover the outlet port 144 and cause the back pressure to increase in conduits 113 and 124. Increase in back pressure in conduits 113 and 124 causes the pressure diaphragm 126 to move the conducting bar 138 outwardly in a manner described previously herein.

As illustrated in FIG; 2, expander 94 is adapted to be slidably movable by expansion of piston 76 when fluid enters chamber 146. Movement of expander 94 causes counter clockwise movement of the bell crank lever or expanding arm 148 about the axis of pin 150. Bell crank lever 148 is caused to pivot by virtue of the upper arm portion 152 being engaged in recess 154 of expander 94. The upper arm portion 152 is held in the recess 154 by an annular end plate 156 which is secured to the bottom of the expander by any conventional means, such as socket head cap screws 158. The lower expanding arm portion 160 of lever 148 is adapted to contact the inner end portion of stone holder 162. Thus, it is apparent that pivoting movement of lever 148 will cause outward radial movement of stone holder 162 for the purpose to be hereinafter disclosed. v

As illustrated in FIG. 4 the body flange assembly includes stone holders 162 adapted to be slidably positioned in radial recesses 164 of annular body flange 166. Each of stone holders 162 are adapted to retain an abrasive stone 168. As best illustrated in FIG. 2, each abrasive stone 168 is detachably retained by clamp plate 1'70 which is detachably secured to stone holder 162 by any conventional means, such as socket head cap screw 172. An annular retaining spring 174 provides for biasing the slidable stone holders inwardly when the expander 94 is moved upwardly which causes the beil crank lever 148 to rotate clockwise about pivot pin 150. Thus, it is readily apparent that during movement of the honing tool into and out of a workpiece, the abrasive stones 168 are withdrawn in the slotted recesses thereby preventing damage thereto.

Mounted on the annular body flange 166 and detachably secured thereto by means of socket head cap screws 177 are bronze guides 176. The bronze guides 176 are radially spaced about the circular periphery of the body flange 166 and provide for guiding the honing tool into and out of the workpiece W.

As illustrated in FIGS. 2 and 4, body flange assembly is mounted to the body 70 by means of socket head cap screws 178. To provide for proper positioning of the body flange assembly 165 with respect to the body portion 70 a drive key 180 is positioned and secured by socket head cap screw 181.

As illustrated in FIG. 2, the honing tool is adapted to contact the workpiece W, shown in dotted line configuration. A major feature of this invention is to provide for lateral adjustment of the body flange holding the abrasive stones so that regardless of the minor variations, the body flange will shift laterally with respect to the drive shaft to compensate for axial misalignment of the workpiece W and the honing tool. Lateral shift also occurs during the honing operation to compensate for any possible eccentric abrasive stone Wear which occurs gradually during stone life. This is accomplished by an annular bronze ring 184, see also FIG. 3. The annular bronze ring 184 includes a pair of diametrically opposed slots or recesses 186 on one side of the annular bronze ring 184 and another pair of diametrically opposed slots or recesses 188 on the opposite side of the annular ring 184. A key 190 is disposed within each slot or recess to provide for any lateral movement of the ring 184. As shown in FIG. 2, pin 192 having one end disposed in bore 191 of key 190 and the other end disposed in each bore 194 of body 70 provides for lateral adjustment of the annular bronze ring 184 in a direction perpendicular to the axis of the honing tool shaft. As evident from FIG. 3 and FIG. 6, keys 190 are adapted to be disposed in recesses or slots 188 which are disposed 90 relative to slots or recesses 186 and extend upwardly into bores (not shown) of upper annular portion 56.

As illustrated in FIG. 3 and FIG. 6 annular bronze ring 184 includes bores 200 spaced circumferentially and each bore adapted to receive a ball 202. The diameter of each ball is slightly larger than the width or thickness of the ring 184. This is to provide facility in lateral shifting of the honing tool body with respect to the driveshaft. However,

it is well understood that shifting of the honing tool body can be accomplished without the balls 202, since shifting can be accomplished by the bronze ring alone. Radial slots or recesses 204, 206 in the annular bronze ring 184 permit coolant and swarf to drain between the balls 202 and the adjacent abutting surfaces, and also adapted to flow between the abutting surfaces and exit through slots or recesses 208. Since the slots or recesses 186 and 188 are disposed 90 relative to each other, universal lateral displacement of the honing tool is permitted. Also by virtue of the longitudinal slots 186 and 188 which permit longitudinal displacement of the keys 190, the honing tool body is aligned parallel to the rotational axis of the honing tool in any laterally displaced position. An annular retaining ring 196 holds the tubular body portion 70 to the honing tool assembly 40 by means of socket head cap screws 198.

Extending longitudinally therethrough but terminating short of the midpoint of shaft 80 is a bar 210. Mounted at the end of shaft 80 is a bushing or cap 212. The lower shaft end and the bushing or cap are drilled and dowels 214 are. pressed in place thus providing a limit or stop means in a manner and for a purpose to be hereinafter described.

As illustrated in FIG. 2, an arbor holder assembly 216 consists of a tubular element 218 having an internal diameter slightly larger than the diameter of bushing or cap 212. The tubular element 218 has a threaded end portion 222 for the purpose to be hereinafter disclosed. The tubular element 218 is adapted to encircle the lower portion of the shaft 80 including the bushing or cap 212. The arbor holder assembly includes an annular stop ring 224 with an annular cushion 226 made of any conventional type of resilient or plastic laminate interposed between the end portion of tubular element 218 and the annular stop ring 224. Socket flat head screws 228 retain the stop ring 224 and the cushion 226 for the purpose to be hereinafter disclosed.

A locator arbor 230 is mounted to the arbor holder assembly 216 in any conventional manner, however, the preferred embodiment illustrated in FIG. 2 includes an internal threaded portion 231 adapted to be threadedly engaged to the threaded end portion 222 of arbor holder assembly 2 16. A lock nut 220 is threaded onto the arbor holder assembly 216 and abuts the locator arbor 230 in a conventional manner that prevents loosening or a disassociation of the locator arbor 230 from the arbor holder assembly 216.

The locator arbor 230 consists of; bore 232 of internal diameter slightly greater than the diameter of the bushing or cap 212; a bore 234 of internal diameter equal to the diameter of bore 210 of shaft 80; and a bore 236 of smaller internal diameter than the diameter of bore 234. The bore 236 is to permit draining of coolant and swarf therethrough.

A coiled compression spring 238, having a diameter slightly less than the bore diameter of bore 210 of the shaft 80 and bore 234 of locator arbor 230, is interposed between the intern-a1 shoulder 235 of locator arbor 230 and a spring guide 240. The spring guide 240 abuts against a ball 242 which is seated in the terminal end of bore 210 of shaft 80. The spring guide 240 includes a larger diameter portion and a smaller stem portion 241. The larger portion includes a shoulder abutting portion that the spring 238 abuts against. The stem portion 241 of the spring guide 240 is adapted to be axially extended within the confines of the spring 238.

In operation, the driveshaft 42 is powered by the drive source (not shown) and is rotated and moved downwardly, as viewed in FIG. 1, causing corresponding rotation of the honing tool assembly 40. Pressure fluid is supplied to the cylinder by a pump preferably of the high volume, high pressure type through a hydraulic circuit of a suitable and well known construction. The honing tool assembly, as illustrated in FIG. 2, is adapted to be moved into position with the workpiece W. The particular workpiece illustrated comprises a conventional brake drum having an interior circumferential Wall the surfaces of which are to be dressed. It will be understood, of course, that external surfaces may be dressed in a similar operation by using an appropriate form of honing tool.

In the non-operating position, the compressive force of the spring 238 is adapted to expand or extend the locator arbor 230 to its extreme position until cushion 226 abuts the bushing or cap 212. As the honing tool assembly is lowered, the brake drum being supported on the fixture frame 14 provides a reactionary force to the locator arbor 230 which causes the arbor to retract or slidably move on the lower portion of shaft until the honing tool sea-ts upon the workpiece. As the tool is lowered into the workpiece W, the locator arbor 230 is adapted to extend through the central opening of the brake drum until bearing surface 250 contacts surface 245 on the arbor 230. The locator arbor 230 is prevented from being withdrawn by an engaging element (not shown) located in the fixture frame 14 which is adapted to engage the hook engaging portion 244 on the locator arbor. If any misalignment exists between the workpiece W and the honing tool assembly 40, the honing tool body portion 70 is shifted laterally by virtue of the bronze ring 184 interposed between the contacting surfaces. Thus, the tool is precisely seated upon the workpiece automatically.

Fluid is caused to enter chamber 146 by means of inlet fluid coupling 246, and is adapted to expand piston 76 thus effecting a downward movement of rod or shaft 80. Downward movement of shaft 80 causes slidable movement of the expander 94 with respect to the honing tool body portion 70. Movement of the expander causes rotation of bell crank lever 148 about pivot pin 150 thus effecting radial movement of stoneholders 16 2 against the inner wall surface of the brake drum. The spindle or quill 26 is rotated through conventional belt and pulley means 28 connected to a motor, not shown. As hereinabove described, integrally connected with the spindle or quill 26 is the honing tool by means of the drive shaft 42 which is adapted to be rotated thus causing a rotation of the abrasive stones against the inner wall surface of the brake drum. Simultaneously, the honing too-l is reciprocated by means of hydraulic cylinder means 20. Thus, the honing tool is reciprocated and rotated to provide the proper surface finish to the inner circumferential wall surface of the brake drum. After a preselected time interval the simultaneous reciprocation and rotation of the honing tool is stopped, and fluid is caused to enter the chamber 252 through the fiuid coupling 248. Fluid enters the chamber 252 by means of a circular recess 254 extending around the piston 76 and thence by means of recesses 256 extending longitudinally in the direction of the chamber 252. Thus fluid is adapted to force the piston 76 upwardly to effect retraction of the abrasive stones. This is accomplished by pivotal movement of bell crank lever 148. With the bell crank lever 148 in its uppermost or furthest clockwise position, the stone holders are permitted to slidably retract under the influence of the springs 174. The honing tool assembly is retracted and the finished workpiece removed.

In the device illustrated in FIG. 1 and FIG. 2, the preferred embodiment shows the locator arbor integral with the honing tool assembly. However, as a modification thereof, the arbor is adapted to be removed and the honing tool operated on a brake drum which is secured to the fixture frame support 14. That is, the brake drum is manually bolted down through the axial opening to the fixture frame support by a conventional nut and bolt means.

While a preferred embodiment of the invention has been illustrated and described herein, it will be apparent to those skilled in the art that various modifications, omissions, additions and substitutions may be made therein without departing from the spirit and scope of the invention, as encompassed in the appended claims.

What is claimed is:

1. In a honing tool, adapted to be rotated and reciprocated, comprising: a circular drive shaft, a circular body housing fixed to said circular drive shaft, a circular body having an upper portion extending within a portion of said drive shaft and a lower portion extending below said circular body housing, said circular body including a plurality of slots, a plurality of hell crank levers pivotally mounted to said body and movable within said slots, a body flange fixed to said circular body, said body flange including a plurality of slots, a plurality of stone holders slidably mounted to said body flange within said slots in said body flange, each of said plurality of stone holders having an abrasive stone fixed thereto, said body includes a shaft extending longitudinally, a piston fixed to one end of said shaft and adapted for slidable movement within said upper portion of said body, a locator arbor slidably mounted on the other end of said shaft and adapted to be fixed and stationary while said honing tool is adapted to be rotated and reciprocated, an expander slida'bly retained within said circular body, and fixed to said shaft, whereby movement of said piston causes movement of said expander, and movement of said expander causes movement of said plurality of stone holders until each of said abrasive said plurality of hell crank levers causes radial movement of said plurality of stone holders until each of said abrasive stones contacts the surface of a workpiece, and means interposed between said body housing and said body adapted for lateral movement of said body with respect to said body housing.

2. In a honing tool as defined in claim 1, wherein the other end of said shaft includes a bore extending midway therein, said locator arbor having a bore extending longitudinally thereof, a spring mounted within said bore of said shaft and extending longitudinally into said bore of said locator arbor, and a stop means fixed to said other end of said shaft whereby said locator arbor is limited in its extent.

a 3. In a honing tool as defined in claim 2, wherein a ball is interposed between one end of said spring and the bore end of said shaft, whereby said locator arbor is adapted to be stationary while said honing tool is rotated and reciprocatcd.

4. In a honing tool, adapted to be rotated and reciprocated, comprising: a circular drive shaft, a circular body housing fixed to said circular drive shaft, a circular body having an upper portion extending within a portion of said drive shaft and a lower portion extending below said circular body housing, a body flange fixed to said circular body, a plurality of abrasive stones mounted on said body flange, and means interposed between said body housing and said body adapted for lateral movement of said body with respect to said body housing, said means comprises a bronze ring having a plurality of recesses, a pair of said recesses adjacent said body housing, and another pair of recesses adjacent said body, key means slidably retained in said recesses, and pin means interconnecting said key means and adapted to be fixed to said body housing and said body respectively, whereby lateral movement of said body with respect to said body housing is attained thereby, and wherein said bronze ring includes a plurality of, bores circumferentially spaced, a plurality of balls, and each of said plurality of balls contained in each of said plurality of bores, whereby lateral movement of said body with respect to said body housing is attained thereby.

References Cited UNITED STATES PATENTS 1,193,884 8/1916 Emery 51348 1,931,986 10/1933 Heuer 51348 X 2,102,053 12/1937 Batzer 51--348 X 2,141,491 12/ 1938 Searles 51-348 X 2,143,454- 1/1939 Schmidt 51348 X 2,213,027 8/1940 Indge 51-347 X 2,262,075 11/1941 Wilhide 51-241 HAROLD D. WHITEHEAD, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0 3,380,197 April 30, 1968 Paul Fitzpatrick It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 26, "stone holders until each of said abrasive" should read bell crank levers and movement of Signed and sealed this 2nd day of December 1969.

(SEAL) Attest:

Edward M. Fletcher, J r.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR. 

